Is anyone using QTR to make digital negatives? If so can or would you spare any details about what you are doing with this RIP (or any other for that matter) ?

Don Bryant

http://www.ronreeder.com/articles/digitalnegs.html

Just in time for Xmas. I've not delved into the curve builder yet, but I looks like it must work if someone has written a section of a book devoted to it...I'm going to try building some curves shortly I'll keep you posted.

Merry Christmas, in deed. This looks interesting.

Don, I picked up QTR because of the ink control options in it. ---That was just before I dropped my PDN calibration work with Azo G3 (first due to lack of Amidol, and then the paper itself, as you know, dissappeared). (I am very pleased with this RIP for printing "inkjet premonitions.") I am getting set up to resume work with PDN on palladium, so I am equally interested to know other's experience with QTR making digital negatives.

You might also want to look into the Bowhaus RIP IJC/OPM. the GUI is a bit more friendly, which translates to easier use. It is of course more expensive. http://www.bowhaus.com/services/IJCOPMmain.php4

I started to test some IJC/OPM profiles for making digital negatives directly from positive images (ie 'inverted' profiles) but got distracted when the K3 inks came out.

Last week I discovered by chance that I could print using a mixture of MIS base, Windex and red dye (from a stamp pad refill - I had to dye the cleaning mixture to see the nozzle test patterns) with an Epson 2200 that wouldn't print with OEM ink. Even after getting perfect prints with the dye, the clogged nozzles wouldn't print with OEM ink. This means that I now have a 2200 that can't be relied upon to print normally, but which seems perfectly capable of printing red dye images. I will resume my tests.

Best,
Helen

http://www.ronreeder.com/articles/digitalnegs.html

Just in time for Xmas. I've not delved into the curve builder yet, but I looks like it must work if someone has written a section of a book devoted to it...I'm going to try building some curves shortly I'll keep you posted.

Interesting, perhaps Ole Saint Nick will drop me off a copy.

Don Bryant

Merry Christmas, in deed. This looks interesting.

Don, I picked up QTR because of the ink control options in it.

Yes I like the ink control options and have wondered how QTR might be able to be used for making digital negatives. However I prefer colorized negatives to black only.

Don Bryant

Yes I like the ink control options and have wondered how QTR might be able to be used for making digital negatives. However I prefer colorized negatives to black only.

Don Bryant

Don, colorized negatives can be made with QTR too. I've set up a printer with QuadToneRip that can print monochrome C, M, Y, K, CY, CM and mixes of two of these colors. For each color I made a QTR setup C and M are made with C and LC or M and LM. CM is a four color mix. CY a three color mix.

For salted paper and albumen I am using CY as printing color. These prints are green. For printing van dyke and cyanotype I take down the ink load percentage in the driver. Of course each process has it's own correctioncurve, but you can integrate these in the QTR setup for each process/color. For short scale techniques like gum I am using 90% CM with 10%Y (purple negatives).

With a dedicated black and white printer I get excellent results on Agfa CopyJet with QuadToneRip by using only grey inks (no K).

Kees,

I've gone through the process of linearizing curves with QTR but I cannot wrap my brain around how to use color inks excluding black inks from the printing process. But even more importantly how would one decide which inks to use?

Don Bryant

You might also want to look into the Bowhaus RIP IJC/OPM. the GUI is a bit more friendly, which translates to easier use. It is of course more expensive. http://www.bowhaus.com/services/IJCOPMmain.php4
I'm sure this is a great product but how would one use it for making digital negatives?

Don Bryant

Kees,

I've gone through the process of linearizing curves with QTR but I cannot wrap my brain around how to use color inks excluding black inks from the printing process. But even more importantly how would one decide which inks to use?

Don Bryant

One method is to use the colours on the fringes on the RGB colour model. Imagine a cube. X, Y and Z planes of the cube each represent RGB respectively. Imagine the cube is 256 blocks in each direction. Pure Reds, Greens and Blues (and their off-spring) only exist on the edge corners of the shell of the cube.

9

The goal is to avoid using the "dirty" black ink that inhabits the centre of the cube. This -- in theory -- produces a better pattern of dots on the negative -- according so some.
Deciding which inks to use is easy. Print a step wedge(s) that shows each of the colour combinations in the area of the cube I just mentioned. Usually, one or two ink combinations will produce a square white enough for the dMax of your emulsion. I'll send you one if you want.

Yes I like the ink control options and have wondered how QTR might be able to be used for making digital negatives. However I prefer colorized negatives to black only.

Don Bryant

Yes, Don, it was my intention to exclude the blacks and print colorized negatives (ala PDN). It sounds like I got about to the point where you are now.

Until the next time,

One method is to use the colours on the fringes on the RGB colour model. Imagine a cube. X, Y and Z planes of the cube each represent RGB respectively. Imagine the cube is 256 blocks in each direction. Pure Reds, Greens and Blues (and their off-spring) only exist on the edge corners of the shell of the cube.

9

The goal is to avoid using the "dirty" black ink that inhabits the centre of the cube. This -- in theory -- produces a better pattern of dots on the negative -- according so some.
Deciding which inks to use is easy. Print a step wedge(s) that shows each of the colour combinations in the area of the cube I just mentioned. Usually, one or two ink combinations will produce a square white enough for the dMax of your emulsion. I'll send you one if you want.

Michael,

The Rubic's cube approach sounds interesting but I'm not sure I understand how to combind that image with QTR. Sometimes I'm a bit slow, perhaps I'm missing the obvious. But please e-mail me a copy of the cube image.

Thanks,

Don

Kees,

I've gone through the process of linearizing curves with QTR but I cannot wrap my brain around how to use color inks excluding black inks from the printing process. But even more importantly how would one decide which inks to use?

Don Bryant

Did you make your own QTR curves too? When you download QTR there is a Curvedesign folder included. I'm using a mac, so maybe this might be a bit different on windows. When you open the Curvedesign folder you find instructions to edit the default inkdescriptor files for your printer. Here you can specify how many inks you use, in what order these inks are used and where each ink takes over from the previous. You can also print a calibration print for this file to help you decide how to edit the inkdescriptor file.

When you run the installerscript with the edited file a new QTR printerprofile/curve is created that you can choose from the QTR driver. After this you can linearize or make a correctioncurve for each process.

The green (CY) negatives have most contrast, Magenta-Yellow (MY) has a bit less contrast and purple CM is low contrast. You can mix in some extra yellow or magenta to finetune from the driver where you can choose two profiles and mix them.

Here is an example of my CM inkdescriptor file: CM.txt (http://hybridphoto.com/forums/attachment.php?attachmentid=10&stc=1&d=1162284601)
I use the normal ink description for the first inkcolor and the toner description position for the other.

Maybe a windows QTR user can tell if this works the same on windows.
Hope this gets you on the way!

kees

I wrote a brief non-technical article for alternativephotography.com that uses the idea of a ternary graph to determine the appropriate mix of colors that block the most Uv (or other) light. It could easily be adapted to CMY space as well (no black). My RGB approach does, of course, use a little black, but the negativesand resulting prints are as good as any I have seen from other approaches.

http://www.alternativephotography.com/articles/art056.html

I downloaded QTR to look at the different settings. There were different algorithms available to choose from, and I wondered if this solved the Venetian blind problem, some of the Epson printers were having?

Also, are there any other printer RIPs available that would allow me to control ink density and print head passes as the R2400 drivers do? I am using an R800.

Regards,
Martin

I also was drawn to QTR because of the variable algorithms and the prospect of this option to resolve banding issues. The wonderful thing about QTR is that its shareware. Other RIPs I looked at were quite expensive.

So does this take care of the banding/venetian blind problem?

Regards,
Martin

I'm sure this is a great product but how would one use it for making digital negatives?

Don Bryant

It does the exact same things that QTR does, except has a better GUI for setting the ink mixing.

Did you make your own QTR curves too?

Yes.


When you download QTR there is a Curvedesign folder included. I'm using a mac, so maybe this might be a bit different on windows. When you open the Curvedesign folder you find instructions to edit the default inkdescriptor files for your printer. Here you can specify how many inks you use, in what order these inks are used and where each ink takes over from the previous. You can also print a calibration print for this file to help you decide how to edit the inkdescriptor file.


I must have an older version. I don't have the Curver Designer.



When you run the installerscript with the edited file a new QTR printerprofile/curve is created that you can choose from the QTR driver. After this you can linearize or make a correctioncurve for each process.

The green (CY) negatives have most contrast, Magenta-Yellow (MY) has a bit less contrast and purple CM is low contrast. You can mix in some extra yellow or magenta to finetune from the driver where you can choose two profiles and mix them.

Here is an example of my CM inkdescriptor file: CM.txt (http://hybridphoto.com/forums/attachment.php?attachmentid=10&stc=1&d=1162284601)
I use the normal ink description for the first inkcolor and the toner description position for the other.

Maybe a windows QTR user can tell if this works the same on windows.
Hope this gets you on the way!

kees

In a nut shell I can turn and turn off inks throught the Curve Designer - ink descriptor file?

I suppose I need to revist QTR as I've not used it in a long while.

Thanks for the insights.

Don